linux-kernel - Re: [PATCH v8 0/4] improvements to the nmi

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Date:   Thu, 18 Aug 2016 16:46:05 +0100
From:   Daniel Thompson <daniel.thompson@...aro.org>
To:     Chris Metcalf <cmetcalf@...lanox.com>,
        Peter Zijlstra <peterz@...radead.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Petr Mladek <pmladek@...e.com>,
        Russell King <linux@....linux.org.uk>,
        Thomas Gleixner <tglx@...utronix.de>,
        Aaron Tomlin <atomlin@...hat.com>,
        Ingo Molnar <mingo@...hat.com>, Andrew Morton <akpm@...l.org>,
        Mark Rutland <mark.rutland@....com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Ralf Baechle <ralf@...ux-mips.org>,
        "David S. Miller" <davem@...emloft.net>,
        sparclinux@...r.kernel.org, x86@...nel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-arch@...r.kernel.org
Subject: Re: [PATCH v8 0/4] improvements to the nmi_backtrace code

On 16/08/16 20:50, Chris Metcalf wrote:
> This is a rebase of the series onto v4.8-rc2, plus some changes from
> various reviewers.
>
> From the version 1 cover letter:
>
>   This patch series modifies the trigger_xxx_backtrace() NMI-based
>   remote backtracing code to make it more flexible, and makes a few
>   small improvements along the way.
>
>   The motivation comes from the task isolation code, where there are
>   scenarios where we want to be able to diagnose a case where some cpu
>   is about to interrupt a task-isolated cpu.  It can be helpful to
>   see both where the interrupting cpu is, and also an approximation
>   of where the cpu that is being interrupted is.  The nmi_backtrace
>   framework allows us to discover the stack of the interrupted cpu.
>
> I've tested that the change works as desired on tile, and build-tested
> x86, arm, mips, and sparc64.  For x86 I confirmed that the generic
> cpuidle stuff as well as the architecture-specific routines are in the
> new cpuidle section.  For arm, mips, and sparc I just build-tested it
> and made sure the generic cpuidle routines were in the new cpuidle
> section, but I didn't attempt to figure out which the
> platform-specific idle routines might be.  That might be more usefully
> done by someone with platform experience in follow-up patches.

You can add runtime testing on arm to the list (I didn't try to exploit 
the new one-line-for-idle feature but there were no regressions). All 
patches:

Tested-by: Daniel Thompson <daniel.thompson@...aro.org>


Daniel.